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\(⑴\)核电站利用原子核链式反应放出的巨大能量进行发电,\(\rlap{_{92}}{^{235}}U\)是核电站常用的核燃料。\(\rlap{_{92}}{^{235}}U\)受一个中子轰击后裂变成\(\rlap{_{56}}{^{144}}Ba\)和\(\rlap{_{36}}{^{89}}Kr\)两部分,并产生________个中子。要使链式反应发生,裂变物质的体积要________\((\)选填“大于”或“小于”\()\)它的临界体积。
\(⑵\)取质子的质量\(m\)\({\,\!}_{p}\)
\(=1.672 6×10\)\({\,\!}^{-}\)
\(kg\),中子的质量\(m\)\({\,\!}_{n}\)
\(=1.674 9×10\)\({\,\!}^{-27}\)
\(kg\),\(α\)粒子的质量\(m\)\({\,\!}_{α}\)
\(=6.646 7×10\)\({\,\!}^{-27}\)
\(kg\),光速\(c=3.0×10\)\({\,\!}^{8}\)
\(m/s\)。请计算\(α\)粒子的结合能。\((\)计算结果保留两位有效数字\()\) \(⑶\)一个静止的铀核\(\rlap{_{92}}{^{232}}\)
\(U(\)原子质量为\(232.037 2 u)\)放出一个\(α\)粒子\((\)原子质量为\(4.002 6 u)\)后衰变成钍核\(\rlap{_{90}}{^{228}}\)
\(Th(\)原子质量为\(228.028 7 u)\)。\((\)已知:原子质量单位\(1 u=1.67×10\)\({\,\!}^{-27}\)
\(kg\),\(1 u\)相当于\(931 MeV)\) \(①\)写出核衰变反应方程; \(②\)算出该核衰变反应中释放出的核能; \(③\)假设反应中释放出的核能全部转化为钍核和\(α\)粒子的动能,则钍核获得的动能有多大?